- Embed The Science and Engineering of Sound video at the top of your blog post
- Watch The Science and Engineering of Sound video by Filmmaker IQ up to 9:40 minute mark
- Add notes or other pieces of information that will help you remember the terms and concepts
Sound Wave – A vibrational disturbance that involves mechanical motion of molecules transmitting energy from one place to another.
Compression – Push of air molecules creating a peak of high pressure.
- Reducing a signal’s output level in relation to its input level to reduce dynamic range.
Rarefaction – A trough of low pressure.
Longitudinal Wave – The repetition of compression and rarefaction creates a longitudinal wave or sound wave.
Wave Form – Changes in air pressure created by the sound wave against time.
Wavelength – Distance between two peaks of a wave.
Velocity – Speed in a given direction.
Amplitude – The magnitude of a sound wave or an electric signal, measured in decibel’s.
Frequency – The # of times per second that a sound source vibrates, expressed in hertz (Hz).
Hertz – Unit of measurement of frequency; numerically equal to cycles per second (cps).
440 Hertz – The standard musicians use to tune instruments, which corresponds to the A note on second space treble clef.
Phase – Factor in the interaction of one wave with another, either acoustically or electronically.
- It also references, in a multiple microphone recording, the place a microphone samples the sound wave in relation to another microphone sampling the same sound wave.
Fundamental Frequency – The lowest frequency a sound source can produce.
- In other words, it is also called the first harmonic or primary frequency which is the lowest, or basic, pitch of a musical instrument. an example is 440 Hertz.
Harmonic – Is a multiple of the fundamental frequency, For example, 880 Hertz is the first harmonic of 440 Hertz.
Octave – The interval between two frequencies that have a tonal ratio of 2:1. For example, 880 Hertz is one octave above 440 Hertz.
Envelope – Describes the shape of a sound over time.
Attack – The time it takes for a sound to build up to full volume.
Decay – How quickly a sound levels off to a sustain.
Sustain – The ongoing sound.
Release – How quickly the sound decays or dissipates after the note is released.
Infrasonic – The range below the frequencies audible to human hearing.
Ultrasonic – The range above the frequencies of human hearing.
Pitch – The subjective perception of frequency – the highness or lowness of a sound.
Sound Frequency Spectrum – The range of frequencies audible to human hearing: about 20 to 20,000 Hz.
Bass – The low range of the audible frequency spectrum; usually from 20 to 320 Hz.
Midrange – The part of the frequency spectrum to which humans are most sensitive; the frequencies between roughly 320 Hz and 2,560 Hz.
Treble – Frequency range between roughly 5,120 Hz and 20,000 Hz, the highest two octaves audible to human hearing in the sound frequency spectrum.
Equalization – A signal-processing device that can boost, attenuate, or shelve frequencies in a sound source or sound system.
Decibel (dB) – A relative and dimensionless unit to measure the ratio of two quantities.
- Decibels are not a static unit measurement, it’s a comparison measurement and you always need a reference.
- Soft whisper around 30 dB SPL to freight train at 100 ft from 70dB SPL up to a jet takeoff from 200 feet registering at 120 dB SPL.
- Safety regulations – 85 dB and below you will be fine for 8 hours.
- Cut that time in half each 3 dB you go up.
- Every 3 dB higher doubles the signal strength.